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                        <h1 id="57-&#x9AD8;&#x7EA7;&#x5904;&#x7406;&#x7F3A;&#x5931;&#x503C;&#x5904;&#x7406;">5.7 &#x9AD8;&#x7EA7;&#x5904;&#x7406;-&#x7F3A;&#x5931;&#x503C;&#x5904;&#x7406;</h1>
<h2 id="&#x5B66;&#x4E60;&#x76EE;&#x6807;">&#x5B66;&#x4E60;&#x76EE;&#x6807;</h2>
<ul>
<li>&#x76EE;&#x6807; <ul>
<li>&#x5E94;&#x7528;isnull&#x5224;&#x65AD;&#x662F;&#x5426;&#x6709;&#x7F3A;&#x5931;&#x6570;&#x636E;NaN</li>
<li>&#x5E94;&#x7528;fillna&#x5B9E;&#x73B0;&#x7F3A;&#x5931;&#x503C;&#x7684;&#x586B;&#x5145;</li>
<li>&#x5E94;&#x7528;dropna&#x5B9E;&#x73B0;&#x7F3A;&#x5931;&#x503C;&#x7684;&#x5220;&#x9664;</li>
<li>&#x5E94;&#x7528;replace&#x5B9E;&#x73B0;&#x6570;&#x636E;&#x7684;&#x66FF;&#x6362;</li>
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<hr>
<p><img src="images/&#x7F3A;&#x5931;&#x503C;.png" alt="&#x7F3A;&#x5931;&#x503C;"></p>
<h2 id="1-&#x5982;&#x4F55;&#x5904;&#x7406;nan">1 &#x5982;&#x4F55;&#x5904;&#x7406;nan</h2>
<ul>
<li><p>&#x83B7;&#x53D6;&#x7F3A;&#x5931;&#x503C;&#x7684;&#x6807;&#x8BB0;&#x65B9;&#x5F0F;(NaN&#x6216;&#x8005;&#x5176;&#x4ED6;&#x6807;&#x8BB0;&#x65B9;&#x5F0F;)</p>
</li>
<li><p>&#x5982;&#x679C;&#x7F3A;&#x5931;&#x503C;&#x7684;&#x6807;&#x8BB0;&#x65B9;&#x5F0F;&#x662F;NaN</p>
<ul>
<li><p>&#x5224;&#x65AD;&#x6570;&#x636E;&#x4E2D;&#x662F;&#x5426;&#x5305;&#x542B;NaN&#xFF1A;</p>
<ul>
<li>pd.isnull(df),</li>
<li>pd.notnull(df)</li>
</ul>
</li>
<li><p>&#x5B58;&#x5728;&#x7F3A;&#x5931;&#x503C;nan:</p>
<ul>
<li><p>1&#x3001;&#x5220;&#x9664;&#x5B58;&#x5728;&#x7F3A;&#x5931;&#x503C;&#x7684;:dropna(axis=&apos;rows&apos;)</p>
<ul>
<li>&#x6CE8;&#xFF1A;&#x4E0D;&#x4F1A;&#x4FEE;&#x6539;&#x539F;&#x6570;&#x636E;&#xFF0C;&#x9700;&#x8981;&#x63A5;&#x53D7;&#x8FD4;&#x56DE;&#x503C;</li>
</ul>
</li>
<li><p>2&#x3001;&#x66FF;&#x6362;&#x7F3A;&#x5931;&#x503C;:fillna(value, inplace=True)</p>
<ul>
<li>value:&#x66FF;&#x6362;&#x6210;&#x7684;&#x503C;</li>
<li>inplace:True:&#x4F1A;&#x4FEE;&#x6539;&#x539F;&#x6570;&#x636E;&#xFF0C;False:&#x4E0D;&#x66FF;&#x6362;&#x4FEE;&#x6539;&#x539F;&#x6570;&#x636E;&#xFF0C;&#x751F;&#x6210;&#x65B0;&#x7684;&#x5BF9;&#x8C61;</li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
<li><p>&#x5982;&#x679C;&#x7F3A;&#x5931;&#x503C;&#x6CA1;&#x6709;&#x4F7F;&#x7528;NaN&#x6807;&#x8BB0;&#xFF0C;&#x6BD4;&#x5982;&#x4F7F;&#x7528;&quot;&#xFF1F;&quot;</p>
<ul>
<li>&#x5148;&#x66FF;&#x6362;&#x2018;?&#x2019;&#x4E3A;np.nan&#xFF0C;&#x7136;&#x540E;&#x7EE7;&#x7EED;&#x5904;&#x7406;</li>
</ul>
</li>
</ul>
<h2 id="2-&#x7535;&#x5F71;&#x6570;&#x636E;&#x7684;&#x7F3A;&#x5931;&#x503C;&#x5904;&#x7406;">2 &#x7535;&#x5F71;&#x6570;&#x636E;&#x7684;&#x7F3A;&#x5931;&#x503C;&#x5904;&#x7406;</h2>
<ul>
<li>&#x7535;&#x5F71;&#x6570;&#x636E;&#x6587;&#x4EF6;&#x83B7;&#x53D6;</li>
</ul>
<pre><code class="lang-python"><span class="hljs-comment"># &#x8BFB;&#x53D6;&#x7535;&#x5F71;&#x6570;&#x636E;</span>
movie = pd.read_csv(<span class="hljs-string">&quot;./data/IMDB-Movie-Data.csv&quot;</span>)
</code></pre>
<p><img src="images/movie.png" alt=""></p>
<h3 id="21-&#x5224;&#x65AD;&#x7F3A;&#x5931;&#x503C;&#x662F;&#x5426;&#x5B58;&#x5728;">2.1 &#x5224;&#x65AD;&#x7F3A;&#x5931;&#x503C;&#x662F;&#x5426;&#x5B58;&#x5728;</h3>
<ul>
<li>pd.notnull()</li>
</ul>
<pre><code>pd.notnull(movie)
</code></pre><pre><code class="lang-python">Rank    Title    Genre    Description    Director    Actors    Year    Runtime (Minutes)    Rating    Votes    Revenue (Millions)    Metascore
<span class="hljs-number">0</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>
<span class="hljs-number">1</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>
<span class="hljs-number">2</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>
<span class="hljs-number">3</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>
<span class="hljs-number">4</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>
<span class="hljs-number">5</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>
<span class="hljs-number">6</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>
<span class="hljs-number">7</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">True</span>    <span class="hljs-keyword">False</span>    <span class="hljs-keyword">True</span>
</code></pre>
<pre><code class="lang-python">np.all(pd.notnull(movie))
</code></pre>
<ul>
<li>pd.isnull()</li>
</ul>
<h3 id="22-&#x5B58;&#x5728;&#x7F3A;&#x5931;&#x503C;nan&#x5E76;&#x4E14;&#x662F;npnan">2.2 &#x5B58;&#x5728;&#x7F3A;&#x5931;&#x503C;nan,&#x5E76;&#x4E14;&#x662F;np.nan</h3>
<ul>
<li>1&#x3001;&#x5220;&#x9664;</li>
</ul>
<p>pandas&#x5220;&#x9664;&#x7F3A;&#x5931;&#x503C;&#xFF0C;&#x4F7F;&#x7528;dropna&#x7684;&#x524D;&#x63D0;&#x662F;&#xFF0C;&#x7F3A;&#x5931;&#x503C;&#x7684;&#x7C7B;&#x578B;&#x5FC5;&#x987B;&#x662F;np.nan</p>
<pre><code class="lang-python"><span class="hljs-comment"># &#x4E0D;&#x4FEE;&#x6539;&#x539F;&#x6570;&#x636E;</span>
movie.dropna()

<span class="hljs-comment"># &#x53EF;&#x4EE5;&#x5B9A;&#x4E49;&#x65B0;&#x7684;&#x53D8;&#x91CF;&#x63A5;&#x53D7;&#x6216;&#x8005;&#x7528;&#x539F;&#x6765;&#x7684;&#x53D8;&#x91CF;&#x540D;</span>
data = movie.dropna()
</code></pre>
<ul>
<li>2&#x3001;&#x66FF;&#x6362;&#x7F3A;&#x5931;&#x503C;</li>
</ul>
<pre><code class="lang-python"><span class="hljs-comment"># &#x66FF;&#x6362;&#x5B58;&#x5728;&#x7F3A;&#x5931;&#x503C;&#x7684;&#x6837;&#x672C;&#x7684;&#x4E24;&#x5217;</span>
<span class="hljs-comment"># &#x66FF;&#x6362;&#x586B;&#x5145;&#x5E73;&#x5747;&#x503C;&#xFF0C;&#x4E2D;&#x4F4D;&#x6570;</span>
<span class="hljs-comment"># movie[&apos;Revenue (Millions)&apos;].fillna(movie[&apos;Revenue (Millions)&apos;].mean(), inplace=True)</span>
</code></pre>
<p>&#x66FF;&#x6362;&#x6240;&#x6709;&#x7F3A;&#x5931;&#x503C;&#xFF1A;</p>
<pre><code class="lang-python"><span class="hljs-keyword">for</span> i <span class="hljs-keyword">in</span> movie.columns:
    <span class="hljs-keyword">if</span> np.all(pd.notnull(movie[i])) == <span class="hljs-keyword">False</span>:
        print(i)
        movie[i].fillna(movie[i].mean(), inplace=<span class="hljs-keyword">True</span>)
</code></pre>
<h3 id="23-&#x4E0D;&#x662F;&#x7F3A;&#x5931;&#x503C;nan&#xFF0C;&#x6709;&#x9ED8;&#x8BA4;&#x6807;&#x8BB0;&#x7684;">2.3 &#x4E0D;&#x662F;&#x7F3A;&#x5931;&#x503C;nan&#xFF0C;&#x6709;&#x9ED8;&#x8BA4;&#x6807;&#x8BB0;&#x7684;</h3>
<p>&#x6570;&#x636E;&#x662F;&#x8FD9;&#x6837;&#x7684;&#xFF1A;</p>
<p><img src="images/&#x95EE;&#x53F7;&#x7F3A;&#x5931;&#x503C;.png" alt="&#x95EE;&#x53F7;&#x7F3A;&#x5931;&#x503C;"></p>
<pre><code class="lang-python">wis = pd.read_csv(<span class="hljs-string">&quot;https://archive.ics.uci.edu/ml/machine-learning-databases/breast-cancer-wisconsin/breast-cancer-wisconsin.data&quot;</span>)
</code></pre>
<p>&#x4EE5;&#x4E0A;&#x6570;&#x636E;&#x5728;&#x8BFB;&#x53D6;&#x65F6;&#xFF0C;&#x53EF;&#x80FD;&#x4F1A;&#x62A5;&#x5982;&#x4E0B;&#x9519;&#x8BEF;&#xFF1A;</p>
<pre><code>URLError: &lt;urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:833)&gt;
</code></pre><p>&#x89E3;&#x51B3;&#x529E;&#x6CD5;&#xFF1A;</p>
<pre><code class="lang-python"><span class="hljs-comment"># &#x5168;&#x5C40;&#x53D6;&#x6D88;&#x8BC1;&#x4E66;&#x9A8C;&#x8BC1;</span>
<span class="hljs-keyword">import</span> ssl
ssl._create_default_https_context = ssl._create_unverified_context
</code></pre>
<p><strong>&#x5904;&#x7406;&#x601D;&#x8DEF;&#x5206;&#x6790;&#xFF1A;</strong></p>
<ul>
<li>1&#x3001;&#x5148;&#x66FF;&#x6362;&#x2018;?&#x2019;&#x4E3A;np.nan<ul>
<li>df.replace(to_replace=, value=)<ul>
<li>to_replace:&#x66FF;&#x6362;&#x524D;&#x7684;&#x503C;</li>
<li>value:&#x66FF;&#x6362;&#x540E;&#x7684;&#x503C;</li>
</ul>
</li>
</ul>
</li>
</ul>
<pre><code class="lang-python"><span class="hljs-comment"># &#x628A;&#x4E00;&#x4E9B;&#x5176;&#x5B83;&#x503C;&#x6807;&#x8BB0;&#x7684;&#x7F3A;&#x5931;&#x503C;&#xFF0C;&#x66FF;&#x6362;&#x6210;np.nan</span>
wis = wis.replace(to_replace=<span class="hljs-string">&apos;?&apos;</span>, value=np.nan)
</code></pre>
<ul>
<li>2&#x3001;&#x5728;&#x8FDB;&#x884C;&#x7F3A;&#x5931;&#x503C;&#x7684;&#x5904;&#x7406;</li>
</ul>
<pre><code class="lang-python"><span class="hljs-comment"># &#x5220;&#x9664;</span>
wis = wis.dropna()
</code></pre>
<h2 id="3-&#x5C0F;&#x7ED3;">3 &#x5C0F;&#x7ED3;</h2>
<ul>
<li>isnull&#x3001;notnull&#x5224;&#x65AD;&#x662F;&#x5426;&#x5B58;&#x5728;&#x7F3A;&#x5931;&#x503C;&#x3010;&#x77E5;&#x9053;&#x3011;<ul>
<li>np.any(pd.isnull(movie))  # &#x91CC;&#x9762;&#x5982;&#x679C;&#x6709;&#x4E00;&#x4E2A;&#x7F3A;&#x5931;&#x503C;,&#x5C31;&#x8FD4;&#x56DE;True</li>
<li>np.all(pd.notnull(movie))  # &#x91CC;&#x9762;&#x5982;&#x679C;&#x6709;&#x4E00;&#x4E2A;&#x7F3A;&#x5931;&#x503C;,&#x5C31;&#x8FD4;&#x56DE;False</li>
</ul>
</li>
<li>dropna&#x5220;&#x9664;np.nan&#x6807;&#x8BB0;&#x7684;&#x7F3A;&#x5931;&#x503C;&#x3010;&#x77E5;&#x9053;&#x3011;<ul>
<li>movie.dropna()</li>
</ul>
</li>
<li>fillna&#x586B;&#x5145;&#x7F3A;&#x5931;&#x503C;&#x3010;&#x77E5;&#x9053;&#x3011;<ul>
<li>movie[i].fillna(value=movie[i].mean(), inplace=True)</li>
</ul>
</li>
<li>replace&#x66FF;&#x6362;&#x5177;&#x4F53;&#x67D0;&#x4E9B;&#x503C;&#x3010;&#x77E5;&#x9053;&#x3011;<ul>
<li>wis.replace(to_replace=&quot;?&quot;, value=np.NaN)</li>
</ul>
</li>
</ul>

                    
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